So picture the scene. You have two children. Generally you put one child in the front and one in the back, both on the passenger side of the car. How long does it take you to walk around to the drivers side?
You would think nano seconds as it isn't a huge distance but you would be wrong. It takes as long as possible because those seconds walking around the car are the last quiet moments you are likely to get until you deposit the children else where! Inside the car you can dimly hear the sound of the children preserving breath ready for a however-long-the-journey-is monologue of their stream of consciousness!
I love them dearly but ever single thought that crosses their minds comes out of their mouths whilst they are in the car. And you are required to listen, and answer appropriately. Or is that just my children on that last bit... or to specify the younger one! So that precious gap of a few seconds before you enter the encloses space is so so needed!